There are currently over 2 million breast cancer survivors in the United States, many of whom experience persistent cancer-related symptoms. Fatigue is the most common and distressing symptom among women successfully treated for breast cancer and causes serious disruption in quality of life. Mind-body interventions such as yoga are popular among cancer patients and have shown beneficial effects on fatigue in other populations; however, yoga trials in cancer are scarce. Based on promising results from a small, single-arm pilot study, the proposed study will evaluate the feasibility, acceptability, and preliminary efficacy of an lyengar yoga intervention for breast cancer survivors with persistent fatigue. In this randomized, controlled trial, 60 breast cancer survivors with persistent cancer-related fatigue will be randomly assigned to yoga or health education control for 12 weeks and followed for 3 months. The aims of the project are to: 1) determine the feasibility and acceptability of a 12-week lyengar yoga intervention for breast cancer survivors with persistent fatigue as compared with health education control; 2) evaluate the effects of yoga vs. health education on fatigue and physical performance in breast cancer survivors with persistent fatigue; and 3) explore the effects of yoga vs. health education on behavioral and immune outcomes associated with cancer- related fatigue, including depressed mood, sleep, pain, proinflammatory cytokine activity, and quality of life. This project will constitute the first randomized, controlled trial of yoga for fatigue in breast cancer survivors and will provide key preliminary data to support a larger efficacy trial. In addition, the study will provide insight into secondary effects of yoga and generate hypotheses about potential mechanisms for intervention effects that can be systematically evaluated in a larger trial. The development of targeted treatments for cancer-related fatigue is critical for maintaining quality of life in the growing population of breast cancer survivors. [unreadable] [unreadable] [unreadable]